> -----Original Message-----
> Date:    Tue, 7 Feb 2006 08:42:31 -0500
> From:    Louis Smogor <[log in to unmask]>
> Subject: unmatched DDR2 memory
>
> Hi,
>
> I have a Dell GX280 that came with a _single_ 512M DDR2 stick of
> memory. I want to upgrade (to run VMplayer) and, of course, have a
> question.
>
> GX280 towers have 4 memory slots, 2 banks of 2. DDR2 memory should be
> purchased in matched pairs, but I already have this singleton. What
> happens if I get another (single) 512 (or any other size) stick and put
> it in slot 2 (not paired with the memory in slot 1)?  Getting a 1 Gig
> pair (2x512) is out of reach, and anyway I hate to "waste" the existing
> 512. I gather that, at least, there will be a performance hit, but I
> assume it's not significant (more than 10%). Right or not?
>
> Thanks,
>
> Lou Smogor
>
>                          PCBUILD's List Owners:
>                       Bob Wright<[log in to unmask]>
>                        Drew Dunn<[log in to unmask]>
>

DDR and DDR2 memory does not NEED to be purchased/installed in matched
pairs, but you will lose the ability to operate in a 'dual-channel' mode.
This is where the performance of the data rate depends on whether or not the
memory timings and speed are 'matched' with one another. You can get one
more 512Mb stick to use in your system. Whether or not the memory performs
at its potential in a great part has to do with it matching the existing
module. SiSoft Sandra, PCWizard or some other hardware diagnostic tool will
give you information regarding the memory frequency and timings as well as
the manufacturer. You can use this information to make an informed decision.
By the way, even memory modules purchased at different times and
manufacturers can still run in Dual-Channel mode. Using cpu-z (v 1.31) which
identifies chipset, processor and memory, a pair of 512Mb sticks of DDR
memory paired with existing 128Mb sticks all ran in dual-channel mode in my
fathers Dell 4600. (PC3200) Make sure that you install the additional memory
module into the right slot (bank) or the PC will not boot. HTH.

Chris Ryan
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